Variation in Sow Body Temperature Following Weaning

Abstract There is limited data available on variation in sow temperature following weaning. The objective of this study was to determine variation (diurnal and with day post-weaning) in rectal (RT) and vulva surface (VT) temperature following weaning. A cross-sectional survey was carried out using 114 multi-parous sows weaned in 7 groups between September and December. Sows were housed in individual stalls and were checked daily for standing reflex from d 4 to 8 post-weaning. Sow RT (measured with a standard thermometer) and VT (measured with an infrared thermal camera) were measured daily [at 06:15 (feeding time), 07:00, 07:30 (heat checking time), 09:00, 11:00, 13:00, 15:00, 17:00, 19:00, 21:00, and 23:00]. A repeated-measures analysis was carried out using PROC MIXED of SAS; models included the fixed effect of either study day or measurement time, and random effect of group. The number of sows exhibiting standing reflex on d 4, 5, 6, 7, and 8 post-weaning was 1, 45, 45, 19, 1, respectively; 3 sows did not exhibit standing reflex. Average VT and RT over the study period were 30.8 ± 3.23 and 38.2 ± 0.60°C, respectively; the correlation between these measurements was 0.08 (P < 0.05). There was considerable day-to-day variation in average VT (range between day: 29.5 to 32.6°C) and to a lesser extent RT (range: 37.7 to 38.5°C). The VT was higher (P < 0.05) on d 3 to 5 post-weaning compared with other days. Also, VT was higher (P < 0.05) between 06:15 and 07:30 than at the other measurement times. There was no clear pattern for either day-to-day or diurnal variation in RT. In conclusion, this study described between-sow variation in RT and VT following weaning. Further research is needed to determine if any of this variation in temperature is associated with the onset of estrus.